The present invention relates to ultrasound systems which measure and image anatomical structures. More particularly, the present invention relates to a method and apparatus for simulating an ultrasound scan wherein the displayed image is spatially associated with a contemporaneous scan of an ultrasound phantom, to be used in an ultrasound training system.
Ultrasound imaging systems are highly complex and sophisticated devices. System operators must be specially trained in the operation of ultrasound imaging systems in order to ensure that accurate and useful information is obtained. The most effective training in the field of ultrasound imaging is the "hands-on" method--a real scan using a real ultrasound system. Ultrasound phantoms of human organs, such as the liver, kidneys and heart, could be constructed to mimic the live model. This, however, would require the construction of many different phantoms to account for the large variations of pathological and normal cases of a given organ. Furthermore, an accurate construction of such a physical phantom would be complicated and expensive. A training system that provides a hands-on experience with a wide variety of anatomical structures and conditions without requiring a large variety of complicated and expensive ultrasound phantoms would be useful in the training of ultrasound system operators.
Medical reproduction systems have been proposed wherein real ultrasound data is collected from real ultrasound scans and stored in a database. The stored data is then played back on a simulated ultrasound unit. One such system is disclosed in U.S. Pat. No. 5,609,485. In this system, the operator of the simulated ultrasound unit manipulates a simulated ultrasound probe over a transmitter which may be attached to a simulated body. The transmitter and a receiver in the simulated probe are used by a "six degrees of freedom" unit to determine the position of the simulated probe with respect to the simulated body. The transmitter/receiver pair have three co-located antennae each which operate on magnetic field principals. A processor determines what portion of the stored ultrasound data corresponds to the current position of the probe. A display unit on the simulated ultrasound unit is operable to display an output based on the portion of the stored ultrasound data determined by the processor. The "six degrees of freedom" unit allows the medical reproduction system to perform as an interactive training tool, providing the opportunity to explore the anatomy as if an actual patient were present.
The medical reproduction system described above has several disadvantages. One disadvantage is that an actual ultrasound system is not used in the training mode for performing ultrasound scans or playing back stored ultrasound data. Other disadvantages arise from the positioning device or "six degrees of freedom" unit of U.S. Pat. No. 5,609,485. A disadvantage of using independently operating positioning devices such as the kind described above is that use of separate positioning hardware adds to the level of complexity and cost of the system, such as an ultrasound training system. A further disadvantage is that the magnetic field used to detect probe position may interfere with, or be affected by, the imaging equipment. Still further, such positioning devices only measure position with respect to the transmitter, which is mounted on or near the imaged object. If the transmitter is not mounted in a proper position with respect to the imaged object, the probe position indicated by the positioning device may be different from the actual probe position. Under such circumstances the simulated ultrasound unit might display an image that is not appropriate or expected for the actual position of the simulated probe over the simulated body.
A need remains for an improved interactive ultrasound training system overcome the above-identified difficulties. It is an object of the present invention to meet this need.